Lectin-Glycan-Mediated Nanoparticle Docking as a Step toward Programmable Membrane Catalysis and Adhesion in Synthetic Protocells.

The spontaneous assembly of nanoscale building blocks into continuous semipermeable membranes is a key requirement for the structuration of synthetic protocells. Engineering the functionality and programmability of these building units provides a step toward more complex cell-like entities with adaptive membrane properties. Inspired by the central role of protein (lectin)-carbohydrate interactions in cellular recognition and adhesion, we fabricate semipermeable polysaccharide-polymer microcapsules (polysaccharidosomes) with intrinsic lectin-binding properties. We employ amphiphilic polysaccharide-polymer membrane building blocks endowed with intrinsic bio-orthogonal lectin-glycan recognition sites to facilitate the reversible noncovalent docking of functionalized polymer or zeolitic nanoparticles on the polysaccharidosomes. We show that the programmed attachment of enzyme-loaded nanoparticles gives rise to a membrane-gated spatially localized cascade reaction within the protocells due to the thermoresponsiveness of the polysaccharidosome membrane, and we demonstrate that extended closely packed networks are produced via reversible lectin-mediated adhesion between the protocells. Our results provide a step toward nanoscale engineering of bioinspired cell-like materials and could have longer-term applications in synthetic virology, protobiology, and microbiosensor and microbioreactor technologies.